Consanguineous marriage and reproduction in Beirut, Lebanon.

Effects of consanguineous marriages on couples' fertility and on offspring mortality were investigated in Beirut through a population-based health survey of 2,752 households. A multistage random sampling procedure was used, and information was obtained from all ever-married women in the household about their reproductive performance and genealogical relationship with spouse; demographic and socioeconomic information was also recorded. Twenty-five percent of all marriages were between relatives, and the spouses were first cousins in approximately 57% of all consanguineous marriages. Total pregnancies, live births, and living children were significantly higher among consanguineous couples than among nonconsanguineous ones, as was the proportion dead among children ever born. However, no difference remained in either fertility or mortality, when allowance was made for socioeconomic status, religious affiliation, and marriage duration. The issue of confounding is discussed, and the lack of significant pattern in the final analysis is interpreted as resulting from a long-term practice of consanguineous marriages.     

The Effect of Inbreeding on Mortality and Morbidity among Telugu-speaking Populations of Kharagpur, West Bengal, India

Increased mortality and morbidity including congenital malformations among the offspring of consanguineous marriages have been widely reported in human populations from different parts of the world. However, there are few studies on the effect of the intensity of inbreeding and different degrees of inbreeding on mortality and morbidity. The present study is an attempt to examine the effects of inbreeding on mortality and morbidity including congenital disorders in different levels of inbreeding among Telugu-speaking populations of Kharagpur, West Bengal, India, based on data collected through extensive pedigrees. The study reveals that the frequency of spontaneous abortions and stillbirths is higher in the offspring of consanguineous marriages than in that of non-consanguineous marriages. A similar effect is also observed in the infant mortality rate, which is known to have a genetic component, but is not seen in the mortality rate of children and juveniles. The rate of morbidity is consistently higher in the offspring of consanguineous marriages with a sex bias in favour of inbred females. The increased morbidity rates in inbred individuals tend to be inversely correlated with the increase in average autosomal inbreeding coefficient. This appears to strengthen Sanghvi’s hypothesis of a decline in the frequency of deleterious genes with intensification of inbreeding through generations. The present study also confirms an increase in genetic disorders with an increase in inbreeding in almost all populations.     

新疆伊犁五个少数民族的近亲结婚

1983年4月至1984年5月,对新疆伊犁哈萨克自治州五个民族的近亲结婚情况进行了调查。调查的婚姻数为维吾尔2553起,哈萨克1079起,回1235起,锡伯1222起,蒙古446起。近亲结婚率与平均近交系数分别为:维吾尔——8.23％与 46.74×10~(-4),回——8.10％与45.07×10~(-4),锡伯——4.66％与24.93×10~(-4),哈萨克——2.87％与11.31×10~(-4)。蒙古——0.45％与 2.80×10~(-4)。解放以来,维吾尔族与回族的近亲结婚率有上升趋势,而锡伯族的则有下降趋势。各族近亲结婚中大部分为亲表亲结婚,但堂亲结婚在维吾尔族的近亲结婚中竟占26.18％,在回族中也占16.00％。1303名近亲结婚子女中的七岁前死亡率(12.89％)及先天性缺陷与遗传性疾病发生率(2.99％)显著高于6370名非近亲结婚子女的相应值(7.65％及0.38％)。     

Effects of consanguineous marriages on fertility among three endogamous groups of Andhra Pradesh

To assess interrelationships between consanguineous marriage and fertility, 3 caste groups in Andhra Pradesh--the Desuri Kapu, an affluent agricultural caste; the Devanga, an artisan caste in the middle range of the hierarchy; and the Mala, a scheduled caste at the bottom--were selected for field study. Consanguineous marriages are an essential part of the social structure in this area of southern India. A total of 2524 marriages were analyzed, of which 46% were consanguineous. 19% of consanguineous marriages were between uncle and niece, 22% were between 1st cousins, and 5% were between more distant cousins. The Devanga had the highest rate of related marriages (48%), followed by the Desuri Kapu (47%) and the Mala (41%). Higher caste individuals, and wealthier persons within each caste, are more likely to marry relatives so they can avoid splitting their properties through dowry of bride price. The consanguineous unions as a whole were significantly more fertile than nonconsanguineous unions. The mean number of pregnancies, live births, and surviving offspring was 4.85, 4.44, and 2.99, respectively, among consanguineous couples compared with 3.41, 3.32, and 2.87, respectively, among nonconsanguineous couples. Although the number of pregnancies and live births was significantly higher among consanguineous couples in all 3 castes compared with nonconsanguineous couples, the difference in the number of surviving children between consanguineous and nonconsanguineous unions was not significant among the wealthier castes. This suggests that child mortality is higher among the offspring of consanguineous unions, despite their greater wealth.     

Ancestral consanguinity and mortality among three endogamous populations of Chittoor District, Andhra Pradesh, India

Consanguineous marriages have been practiced around the globe by many societies from time immemorial, particularly in South India. Consanguineous marriages play a major role in the health of a population, and diseases leading to mortality of the progeny are a consequence of detrimental recessive genes. To evaluate the effects of ancestral consanguinity on mortality in relation to consanguineous marriage, we have ascertained data from 1,500 women belonging to three endogamous communities (Akuthota Reddy, Odde, and Madiga) of Chittoor District, Andhra Pradesh, India. There were 500 women from each community. For each marriage we drew a family pedigree, extended upward to two earlier generations on either side of the spouses, to determine the prevalence and pattern of consanguinity, with detailed information on fertility and mortality. We observed a significant difference in the mortality rates between consanguineous and nonconsanguineous marriages when all the marriages of the women, women's parents, and (women's) husband's parents were considered in all three communities. In inbreeding, the offspring of earlier generations might have passed on deleterious genes to later generations (under unfavorable conditions), which resulted in a negative aspect of reproduction (among the offspring of the present couple).     

Determinants of infant and child mortality in the West Bank and Gaza Strip

Infant and child mortality in the West Bank and Gaza Strip has steadily reduced since 1967, even though fertility has remained extremely high. In this paper the determinants of infant and child mortality are discussed, with particular emphasis on the role of consanguineous marriages, short birth spacing and maternal education. It is shown that short birth spacings and type of marriage are more important determinants of infant mortality than maternal education. Moreover, the relative role of consanguineous marriages appears to increase with time.     

Trends of consanguineous marriages in a Sunni Muslim population of West Bengal, India

The Muslim population of the Chaltaberia village in the district of South 24 Parganas in West Bengal is divided into several wards (paras) inhabited by people of specific surnames. The frequency of endogamous marriages within surnames is greater than randomly expected ones. An incomplete reproductive isolation is observed among the five dominant surnames. Consanguineous marriages occur more often outside the village than inside. Leaving out marriages between long distances, a small median distance of 6.36 km is recorded. The neighborhood area works up to be 552.2 km2, which is rather small. There is an underlying process of breeding isolation by distance. A generation length of 21 years has been used for examining the temporal change in consanguineous marriages and inbreeding, which generally appears to increase. There is a general trend of decline in consanguineous marriages towards the southern part of West Bengal and eastern part of Assam among the Bengalee Muslims. The frequency of consanguineous marriages is 7.3% out of all marriages (N=1153) that have taken place in six generations in the population. The first cousin marriage is nearly 50% of all marriages. Patrilineal marriages are common in marriages between second and third cousins. An increase of consanguineous marriages in the younger generation was observed, but the total frequency agrees with a general trend of a decline in the frequency of consanguineous marriages among the Muslims in this part of India.     

Consanguineous marriages in Beirut: Time trends,spatial distribution

Abstract

Twenty‐five per cent of all marriages are consanguineous in a population‐based sample of couples from Beirut. Marriages between distant relatives decline with time, while first‐cousin marriages remain relatively stable. Among first‐cousin marriages, the proportions of father's brother's daughter marriages (37 per cent) and of patrilateral unions (48 per cent) are particularly low. A spatial representation demonstrates an uneven distribution of consanguineous marriages, and an association of high levels of endogamy with Muslim religion, low educational level, and low occupational status.     

Community perceptions of reasons for preference for consanguineous marriages in Pakistan

Although the recent Pakistan Demographic and Health Survey (DHS) show that two-thirds of marriages in Pakistan are consanguineous, the sociocultural determinants of such marriages remain largely unexplored. This paper examines the relative importance of the three commonly perceived reasons for such marriages: religious, economic and cultural. The analysis is based on qualitative data collected in 1995 from multi-ethnic and multi-religious communities in Karachi, the largest city of Pakistan. Results show that consanguineous marriages are preferred across all ethnic and religious groups to a varying degree, and that parents continue to be the prime decision-makers for marriages of both sons and daughters. The major reasons for a preference for consanguineous marriages are sociocultural rather than any perceived economic benefits, either in the form of consolidation of family property or smaller and less expensive dowries. Among Muslims, following religious traditions is the least commonly cited reason for such marriages. Despite the reported sociocultural advantages of consanguineous marriages, such unions are perceived to be exploitative as they perpetuate the existing power structures within the family.     

Incidence of Friedreich ataxia in Italy estimated from consanguineous marriages

The frequency of consanguineous marriages up to second-cousin degree has been carefully established in the past for each of the 95 Italian provinces using the Archive of about 500,000 dispensations given by the Catholic church for such marriages over a 55-year period. It has therefore been possible to compare the frequency of consanguineous marriages observed among 83 couples of parents of Friedreich patients with the frequency of consanguineous marriages of the same degree in the different Italian provinces during the same years. From these data, an estimate of the incidence of the disease has been obtained for the whole nation (between 1/22,000 and 1/25,000). In Southern Italy, where 16 out of the 18 consanguineous marriages among Friedreich parents are concentrated, the incidence of the disease is similar (between 1/25,000 and 1/28,000). This study indicates that the Archive of consanguinity existing in Italy allows a reliable comparison of the frequency of consanguineous marriages among parents of patients with that of the general population. The same method can therefore be applied to the study of incidence of other autosomal recessive disorders in Italy.     

The prevalence and correlates of consanguineous marriages in Yemen: similarities and contrasts with other Arab countries

Using data on 9762 women from the 1997 Yemen Demographic and Maternal and Child Health Survey, this paper examines the prevalence and socioeconomic correlates of consanguineous marriages in Yemen. The results indicate that 40% of marriages are consanguineous, over 85% of which are between first cousins. The prevalence of consanguineous marriages appears to have increased over time, particularly for the last marriage cohort. As for socioeconomic correlates, the study confirms the inverse association between consanguineous marriages and women's education and occupation, age at marriage and economic status. However, no statistically significant difference in the prevalence of consanguinity has been found by place of residence and geographical region. Somewhat unexpected results have been obtained by husband's background characteristics, with higher educated men and those working in the modern sector of the economy being more likely to be married to cousins.     

The practice of consanguineous marriage in oman: prevalence, trends and determinants

The practice of consanguineous marriage has been the culturally preferred form of marriage in most Arab and the Middle Eastern countries, including Oman, but due to a paucity of population-based data in the past there is a dearth of information about its form and dynamics in Oman. Recent national-level surveys allow this gap to be filled. This paper examines the prevalence, trends and determinants of consanguineous marriages in Oman using data from the 2000 Oman National Health Survey. The results indicate a very high prevalence of consanguineous marriage in Oman, as more than half (52%) of marriages are consanguineous. First cousin unions are the most common type of consanguineous unions, constituting 39% of all marriages and 75% of all consanguineous marriages. The study observed various patterns of consanguinity, some of them common with other Arab nations, and some unique in nature. Women's age at marriage, employment, place of childhood residence and geographical region appear to be significant determinants of consanguineous marriages. Consanguineous marriage shows a strong association with marital stability, early age at marriage and early-age childbearing. There has been no appreciable change in the prevalence of consanguineous unions in Oman over the last four decades despite massive socioeconomic development and modernization. However, recent marriage cohorts show slight declining trends. The results suggest that consanguinity is likely to remain stable in the future or decline at a slow rate. Specific health education and genetic counselling should be followed in line with WHO recommendations to minimize the negative health consequences of consanguinity for child health.     

Spatial and temporal variation of consanguinity in Italy

Genetic structure of Italian population is described as regards the level of inbreeding measured through the frequency of consanguineous marriages during a long period of time in different geographical areas. Analyses of spatial and temporal variation of the different types of marriages between close biological relatives allow us to point out the major factors responsible for the availability of cousins to marry within a specific area: population size, fertility, mortality and migration rates and, in general the demographic structure, changing over time and greatly affected by variation in the socio-economic structure. A deepened analysis, within each consanguinity degree, of the various pedigrees differing in the sex of ancestors, give information on the type of migration (patrilocal or matrilocal) occurred in various parts of Italy, as probable consequence of differential type of economy (for instance: pastoral or agricultural in Sardinia). Moreover, a cultural factor of varying intensity could be recognized in the greater observed frequency of marriages in which the nearest ancestors are females, interpreted as a tendency to maintain family ties by mothers of consanguineous mates.     

Parental consanguinity as a cause for increased incidence of births defects in a study of 238,942 consecutive births.

The risk for birth defects in the offspring of first-cousin matings has been estimated to increase sharply compared to non consanguineous marriages. As a general decline in the frequency of consanguineous marriages was observed in this century, one wonders whether consanguinity is still a factor in the appearance of birth defects in developed countries. Based on our registry of congenital anomalies we tried to answer to this question. In the population studied in North-Eastern France a consanguineous mating was known in 1.21% of the cases with congenital anomalies, vs. 0.27% in controls, (p < 0.001). The frequency of the malformations recorded paralleled the degree of consanguinity: out of 89 malformed children, 51 were seen in first-cousins mating (10.3 times more frequent than in offspring of non consanguineous couples), 17 in second-cousins marriages and 18 in more distant relatives mating. Three were uncle-niece marriage. Excluding known mendelian conditions these numbers were 73, 36, 17 and 17 respectively and the corresponding relative risk were 3.68, 3.01, 3.41 and 4.89 respectively. Therefore there is a negative dose-response effect between level of inbreeding and risk of congenital malformations. Consanguineous mothers were more often pregnant than non consanguineous mothers (p < 0.01) and they had more stillbirths than non consanguineous mothers. These results show that consanguinity is still a factor of birth defects and they must be taken into account for genetic counseling of inbred marriages, in developed countries.     

Consanguineous marriages in the province of Antalya, Turkey

To assess the trends in the frequency and the medical effects of consanguinity in the south coast of Turkish population using local and national data in the last 11 years. This cross-sectional study was carried out in Manavgat province, which is a major tourism center on the Mediterranean coast of Turkey. The authors studied consanguineous marriages in rural and urban population in the Mediterranean coast, Manavgat province, Turkey, via a 1500 random survey sample of married couples. There has been a significant increase in the incidence of consanguineous marriages in rural areas (40.7%) since 1989 in the southern population of Turkey. The results showed that the most frequent type of marriage was between the first cousins. It is found that there is no statistically significant difference between the consanguineous and non-consanguineous marriages in the different age groups. The results were discussed on the basis of educational status, reasons for having consanguineous marriages and the general medical effects as well as with the relation of congenital malformations. The custom of consanguineous unions in the Mediterranean population of Turkey is still extremely high, and preventive measures should be done to decrease its frequency and associated complications.     

Inbreeding patterns in La Cabrera, Spain: dispensations, multiple consanguinity analysis, and isonymy

Marital structure and inbreeding coefficients were analyzed in La Cabrera, an isolated mountain region in northwestern Spain. A total of 5,714 marriages were celebrated from 1880 to 1989 in the 37 parishes of the area. The total frequency of consanguineous marriages (up to the fourth degree) is 23.05%; multiple consanguineous marriages are remarkably common, reaching 5.43% of the total. The first cousin/second cousin ratio (referred to as kinship-type frequencies) is 0.43. The inbreeding values are the highest recorded in Spain and in Europe: alpha3 is 4.82 x 10(-3) for the whole period and alpha4 is 6.78 x 10(-3) for 1880--1919. The temporal trend of inbreeding shows high values (alpha3 > 4.5 x 10(-3)) for a particularly long period (1900--1959) and a rapid decline from 1960 onward. This historical inbreeding trend is clearly related to changes in population size. The frequencies of multiple consanguineous marriages and the analysis of isonymy show that the inbreeding structure is related to geographic and demographic factors. Comparing the results at two hierarchical levels (La Cabrera as a whole and the 37 parishes individually), we conclude that the inbreeding values are affected by internal geographic subdivision of the population (Wahlund effect). Social and cultural factors, such as avoidance of or preference for consanguineous marriages, are less important but depend on the kinship type involved.     

Inbreeding and matrimonial structure in a Pyrenean community (Ansó, Huesca, Spain), 1712-1982

Using data from parish records from 1712 to 1982 in a Spanish Pyrenean village, Ansó, the effects of the raw nuptiality, the types of consanguineous marriages and the rate and evolution of inbreeding on the mating structure have been studied. This structure has been modified in the course of time mostly through the secular variations in the frequency of consanguineous marriages. Recent inbreeding decrease in Ansó is related to the population diminution and cultural changes associated with isolate breakdown.     

Consanguineous marriages in Afghanistan

The present cross-sectional study was done in order to illustrate the prevalence and types of consanguineous marriages among Afghanistan populations. Data on types of marriages were collected using a simple questionnaire. The total number of couples in the study was 7140 from the following provinces: Badakhshan, Baghlan, Balkh, Bamyan, Kabul, Kunduz, Samangan and Takhar. Consanguineous marriages were classified by the degree of relationship between couples: double first cousins, first cousins, first cousins once removed, second cousins and beyond second cousins. The coefficient of inbreeding (F) was calculated for each couple and the mean coefficient of inbreeding (α) estimated for each population. The proportion of consanguineous marriages in the country was 46.2%, ranging from 38.2% in Kabul province to 51.2% in Bamyan province. The equivalent mean inbreeding coefficient (α) was 0.0277, and ranged from 0.0221 to 0.0293 in these two regions. There were significant differences between provinces for frequencies of different types of marriages (p<0.001). First cousin marriages (27.8%) were the most common type of consanguineous marriages, followed by double first cousin (6.9%), second cousin (5.8%), beyond second cousin (3.9%) and first cousin once removed (1.8%). There were significant differences between ethnic groups for the types of marriages (χ2=177.6, df=25, p<0.001). Tajiks (Soni) and Turkmens (also Pashtuns) showed the lowest (α=0.0250) and highest (α=0.0297) mean inbreeding coefficients, respectively, among the ethnic groups in Afghanistan. The study shows that Afghanistan's populations, like other Islamic populations, have a high level of consanguinity.